Our research is driven by the aim to understand bioenergetic principles that enable energy transformation and CO2 fixation in green organisms. Energy metabolism is the fundamental driver of all life and its plasticity permits acclimation and adaptation in response to the environment. We aim at understanding how this plasticity remodels the structure and function of photosynthetic processes in response to environmental cues. These acclimation strategies are dynamic and often transient. They are linked to redox- and/or secondary ion mediated regulatory processes as well as to post-translational modifications such as phosphorylation, N-glycosylation, lysine acetylation, tryptophan oxidation and S-nitrosylation. As a main experimental model, we are using the green alga Chlamydomonas reinhardtii. To measure dynamic transitions we are employing fast optical spectroscopy and mass spectrometry. For genetic manipulation of our experimental models, we are using chloroplast and nuclear transformation techniques. We also take advantage of mutant libraries and CRISPR/Cas technology.